Add option to put the onion skin behind the sprite

Fix #526 and fix #412

data/pref.xml

@@ -200,6 +200,7 @@
       <option id="type" type="OnionskinType" default="OnionskinType::MERGE" migrate="Onionskin.Type" />
       <option id="loop_tag" type="bool" default="true" />
       <option id="current_layer" type="bool" default="false" />
+      <option id="position" type="render::OnionskinPosition" default="render::OnionskinPosition::BEHIND" />
     </section>
     <section id="save_copy">
       <option id="filename" type="std::string" />

data/widgets/timeline_conf.xml

@@ -18,6 +18,10 @@
 
     <check id="loop_tag" text="Loop through tag frames" cell_hspan="2" />
     <check id="current_layer" text="Current layer only" cell_hspan="2" />
+    <hbox cell_hspan="2">
+      <radio group="2" text="Behind sprite" id="behind" tooltip="Only for transparent layers.&#10;Background is not included in this onion skin mode." tooltip_dir="top" />
+      <radio group="2" text="In front of sprite" id="infront" tooltip="For all kind of layers (background and transparents)" />
+    </hbox>
   </grid>
 </vbox>
 </gui>

src/app/pref/preferences.h

@@ -22,6 +22,7 @@
 #include "doc/layer_index.h"
 #include "filters/tiled_mode.h"
 #include "gfx/rect.h"
+#include "render/onionskin_position.h"
 
 #include "generated_pref_types.h"
 

src/app/ui/configure_timeline_popup.cpp

@@ -54,6 +54,8 @@ ConfigureTimelinePopup::ConfigureTimelinePopup()
   m_box->resetOnionskin()->Click.connect(Bind<void>(&ConfigureTimelinePopup::onResetOnionskin, this));
   m_box->loopTag()->Click.connect(Bind<void>(&ConfigureTimelinePopup::onLoopTagChange, this));
   m_box->currentLayer()->Click.connect(Bind<void>(&ConfigureTimelinePopup::onCurrentLayerChange, this));
+  m_box->behind()->Click.connect(Bind<void>(&ConfigureTimelinePopup::onPositionChange, this));
+  m_box->infront()->Click.connect(Bind<void>(&ConfigureTimelinePopup::onPositionChange, this));
 }
 
 app::Document* ConfigureTimelinePopup::doc()
@@ -92,6 +94,15 @@ void ConfigureTimelinePopup::updateWidgetsFromCurrentSettings()
       m_box->tint()->setSelected(true);
       break;
   }
+
+  switch (docPref.onionskin.position()) {
+    case render::OnionskinPosition::BEHIND:
+      m_box->behind()->setSelected(true);
+      break;
+    case render::OnionskinPosition::INFRONT:
+      m_box->infront()->setSelected(true);
+      break;
+  }
 }
 
 bool ConfigureTimelinePopup::onProcessMessage(ui::Message* msg)
@@ -142,6 +153,7 @@ void ConfigureTimelinePopup::onResetOnionskin()
   docPref.onionskin.opacityStep(docPref.onionskin.opacityStep.defaultValue());
   docPref.onionskin.loopTag(docPref.onionskin.loopTag.defaultValue());
   docPref.onionskin.currentLayer(docPref.onionskin.currentLayer.defaultValue());
+  docPref.onionskin.position(docPref.onionskin.position.defaultValue());
 
   updateWidgetsFromCurrentSettings();
 }
@@ -156,4 +168,11 @@ void ConfigureTimelinePopup::onCurrentLayerChange()
   docPref().onionskin.currentLayer(m_box->currentLayer()->isSelected());
 }
 
+void ConfigureTimelinePopup::onPositionChange()
+{
+  docPref().onionskin.position(m_box->behind()->isSelected() ?
+                               render::OnionskinPosition::BEHIND:
+                               render::OnionskinPosition::INFRONT);
+}
+
 } // namespace app

src/app/ui/configure_timeline_popup.h

@@ -39,6 +39,7 @@ namespace app {
     void onResetOnionskin();
     void onLoopTagChange();
     void onCurrentLayerChange();
+    void onPositionChange();
 
   private:
     void updateWidgetsFromCurrentSettings();

src/app/ui/editor/editor.cpp

@@ -460,6 +460,7 @@ void Editor::drawOneSpriteUnclippedRect(ui::Graphics* g, const gfx::Rect& sprite
             render::OnionskinType::RED_BLUE_TINT:
             render::OnionskinType::NONE)));
 
+        opts.position(docPref.onionskin.position());
         opts.prevFrames(docPref.onionskin.prevFrames());
         opts.nextFrames(docPref.onionskin.nextFrames());
         opts.opacityBase(docPref.onionskin.opacityBase());

src/app/widget_loader.cpp

@@ -471,6 +471,7 @@ void WidgetLoader::fillWidgetWithXmlElementAttributes(const TiXmlElement* elem,
   const char* id        = elem->Attribute("id");
   const char* text      = elem->Attribute("text");
   const char* tooltip   = elem->Attribute("tooltip");
+  const char* tooltip_dir = elem->Attribute("tooltip_dir");
   bool selected         = bool_attr_is_true(elem, "selected");
   bool disabled         = bool_attr_is_true(elem, "disabled");
   bool expansive        = bool_attr_is_true(elem, "expansive");
@@ -503,12 +504,20 @@ void WidgetLoader::fillWidgetWithXmlElementAttributes(const TiXmlElement* elem,
   if (text)
     widget->setText(text);
 
-  if (tooltip != NULL && root != NULL) {
+  if (tooltip && root) {
     if (!m_tooltipManager) {
       m_tooltipManager = new ui::TooltipManager();
       root->addChild(m_tooltipManager);
     }
-    m_tooltipManager->addTooltipFor(widget, tooltip, LEFT);
+
+    int dir = LEFT;
+    if (tooltip_dir) {
+      if (strcmp(tooltip_dir, "top") == 0) dir = TOP;
+      else if (strcmp(tooltip_dir, "bottom") == 0) dir = BOTTOM;
+      else if (strcmp(tooltip_dir, "left") == 0) dir = LEFT;
+      else if (strcmp(tooltip_dir, "right") == 0) dir = RIGHT;
+    }
+    m_tooltipManager->addTooltipFor(widget, tooltip, dir);
   }
 
   if (selected)

src/render/render.cpp

@@ -462,7 +462,8 @@ void Render::renderLayer(
     return;
 
   m_globalOpacity = 255;
-  renderLayer(layer, dstImage, area,
+  renderLayer(
+    layer, dstImage, area,
     frame, Zoom(1, 1), scaled_func,
     true, true, blend_mode);
 }
@@ -521,13 +522,39 @@ void Render::renderSprite(
       break;
   }
 
-  // Draw the current frame.
+  // Draw the background layer.
   m_globalOpacity = 255;
   renderLayer(
     m_sprite->folder(), dstImage,
     area, frame, zoom, scaled_func,
-    true, true, BlendMode::UNSPECIFIED);
+    true,
+    false,
+    BlendMode::UNSPECIFIED);
 
+  // Draw onion skin behind the sprite.
+  if (m_onionskin.position() == OnionskinPosition::BEHIND)
+    renderOnionskin(dstImage, area, frame, zoom, scaled_func);
+
+  // Draw the transparent layers.
+  m_globalOpacity = 255;
+  renderLayer(
+    m_sprite->folder(), dstImage,
+    area, frame, zoom, scaled_func,
+    false,
+    true,
+    BlendMode::UNSPECIFIED);
+
+  // Draw onion skin in front of the sprite.
+  if (m_onionskin.position() == OnionskinPosition::INFRONT)
+    renderOnionskin(dstImage, area, frame, zoom, scaled_func);
+}
+
+void Render::renderOnionskin(
+  Image* dstImage,
+  const gfx::Clip& area,
+  frame_t frame, Zoom zoom,
+  RenderScaledImage scaled_func)
+{
   // Onion-skin feature: Draw previous/next frames with different
   // opacity (<255)
   if (m_onionskin.type() != OnionskinType::NONE) {
@@ -563,18 +590,23 @@ void Render::renderSprite(
         m_globalOpacity = m_onionskin.opacityBase() - m_onionskin.opacityStep() * ((frameOut - frame)-1);
       }
 
-      if (m_globalOpacity > 0) {
       m_globalOpacity = MID(0, m_globalOpacity, 255);
-
+      if (m_globalOpacity > 0) {
         BlendMode blend_mode = BlendMode::UNSPECIFIED;
         if (m_onionskin.type() == OnionskinType::MERGE)
           blend_mode = BlendMode::NORMAL;
         else if (m_onionskin.type() == OnionskinType::RED_BLUE_TINT)
           blend_mode = (frameOut < frame ? BlendMode::RED_TINT: BlendMode::BLUE_TINT);
 
-        renderLayer(onionLayer, dstImage,
+        renderLayer(
+          onionLayer, dstImage,
           area, frameIn, zoom, scaled_func,
-                    true, true, blend_mode);
+          // Render background only for "in-front" onion skinning and
+          // when opacity is < 255
+          (m_globalOpacity < 255 &&
+           m_onionskin.position() == OnionskinPosition::INFRONT),
+          true,
+          blend_mode);
       }
     }
   }

src/render/render.h

@@ -16,6 +16,7 @@
 #include "gfx/fwd.h"
 #include "gfx/size.h"
 #include "render/extra_type.h"
+#include "render/onionskin_position.h"
 #include "render/zoom.h"
 
 namespace gfx {
@@ -50,6 +51,7 @@ namespace render {
   public:
     OnionskinOptions(OnionskinType type)
       : m_type(type)
+      , m_position(OnionskinPosition::BEHIND)
       , m_prevFrames(0)
       , m_nextFrames(0)
       , m_opacityBase(0)
@@ -59,6 +61,7 @@ namespace render {
     }
 
     OnionskinType type() const { return m_type; }
+    OnionskinPosition position() const { return m_position; }
     int prevFrames() const { return m_prevFrames; }
     int nextFrames() const { return m_nextFrames; }
     int opacityBase() const { return m_opacityBase; }
@@ -67,6 +70,7 @@ namespace render {
     Layer* layer() const { return m_layer; }
 
     void type(OnionskinType type) { m_type = type; }
+    void position(OnionskinPosition position) { m_position = position; }
     void prevFrames(int prevFrames) { m_prevFrames = prevFrames; }
     void nextFrames(int nextFrames) { m_nextFrames = nextFrames; }
     void opacityBase(int base) { m_opacityBase = base; }
@@ -76,6 +80,7 @@ namespace render {
 
   private:
     OnionskinType m_type;
+    OnionskinPosition m_position;
     int m_prevFrames;
     int m_nextFrames;
     int m_opacityBase;
@@ -160,6 +165,12 @@ namespace render {
       const gfx::Clip& area,
       int opacity, BlendMode blend_mode, Zoom zoom);
 
+    void renderOnionskin(
+      Image* image,
+      const gfx::Clip& area,
+      frame_t frame, Zoom zoom,
+      RenderScaledImage scaled_func);
+
     void renderLayer(
       const Layer* layer,
       Image* image,